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Results for “Environmental Monitoring and Assessment”

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At least 73 records · Page 4Linked to original sources
USGS2025

Regional high-frequency monitoring revealed chloride concentrations in exceedance of ecological benchmarks in urban streams across the Delaware River Basin, USA

Rising chloride concentrations pose critical risks to freshwater stream ecosystems in temperate regions like the Delaware River Basin (DRB), USA, where winter deicer applications ( i.e. , road salt) are common. Increasing chloride concentrations have been documented in the region, but the extent to which chloride exceeds regulatory benchmarks remains unclear because detection of exceedances requires continuous monitoring of chloride ( i.e. , hourly or daily). A network of 82 non-tidal continuous specific conductance (SC) monitoring sites, spanning varied land use and geological settings, was established across the DRB to address this research need. First, a cluster analysis was conducted to group sites based on their watershed characteristics. Next, regression models for sites and clusters were developed to predict chloride using SC as a proxy. Finally, daily mean and hourly mean chloride concentration predictions were made for a three-year period (2020–2022) at the 82 study sites and analyzed to determine where and when chloride exceeded federal regulatory benchmarks. Chloride exceedance events occurred at 35% of the sites, all of which had 5% impervious cover or greater. Seasonally elevated chloride also was predicted at sites with less than 5% impervious cover. Variability in chloride patterns likely was influenced by deicer material types, winter weather patterns, geological settings, and gaps in data coverage. This study demonstrated the value of SC as a proxy for predicting chloride concentrations and showed how SC-chloride regression relationships vary across settings. More broadly, this study highlighted the value of continuous water quality monitoring to assess effects of freshwater salinization at a regional scale.

Delaware, Maryland, New Jersey, New York, Pennsylv↗
USGS2006

Can basin land use effects on physical characteristics of streams be determined at broad geographic scales?

The environmental setting (e.g., climate, topography, geology) and land use affect stream physical characteristics singly and cumulatively. At broad geographic scales, we determined the importance of environmental setting and land use in explaining variation in stream physical characteristics. We hypothesized that as the spatial scale decreased from national to regional, land use would explain more of the variation in stream physical characteristics because environmental settings become more homogeneous. At a national scale, stepwise linear regression indicated that environmental setting was more important in explaining variability in stream physical characteristics. Although statistically discernible, the amount of variation explained by land use was not remarkable due to low partial correlations. At level II ecoregion spatial scales (southeastern USA plains, central USA plains, and a combination of the western Cordillera and the western interior basins and ranges), environmental setting variables were again more important predictors of stream physical characteristics, however, as the spatial scale decreased from national to regional, the portion of variability in stream physical characteristics explained by basin land use increased. Development of stream habitat indicators of land use will depend upon an understanding of relations between stream physical characteristics and environmental factors at multiple spatial scales. Smaller spatial scales will be necessary to reduce the confounding effects of variable environmental settings before the effects of land use can be reliably assessed.

Environmental Monitoring and Assessment↗
USGS2006

Dermal insecticide residues from birds inhabiting an orchard

The US Environmental Protection Agency conducts risk assessments of insecticide applications to wild birds using a model that is limited to the dietary route of exposure. However, free-flying birds are also exposed to insecticides via the inhalation and dermal routes. We measured azinphos-methyl residues on the skin plus feathers and the feet of brown-headed cowbirds ( Molothrus ater ) in order to quantify dermal exposure to songbirds that entered and inhabited an apple ( Malus x domestica ) orchard following an insecticide application. Exposure to azinphos-methyl was measured by sampling birds from an aviary that was built around an apple tree. Birds sampled at 36 h and 7-day post-application were placed in the aviary within 1 h after the application whereas birds exposed for 3 days were released into the aviary 4-day post-application. Residues on vegetation and soil were also measured. Azinphos-methyl residues were detected from the skin plus feathers and the feet from all exposure periods. Our results underscore the importance of incorporating dermal exposure into avian pesticide risk assessments.

Environmental Monitoring and Assessment↗
USGS2002

Indicators of wetland condition for the Prairie Pothole Region of the United States

We describe a study designed to evaluate the performance ofwetland condition indicators of the Prairie Pothole Region (PPR)of the north central United States. Basin and landscape scaleindicators were tested in 1992 and 1993 to determine theirability to discriminate between the influences of grasslanddominated and cropland dominated landscapes in the PPR. Pairedplots were selected from each of the major regions of the PPR.Among the landscape scale indicators tested, those most capableof distinguishing between the two landscapes were: 1) frequencyof drained wetland basins, 2) total length of drainage ditch perplot, 3) amount of exposed soil in the upland subject to erosion,4) indices of change in area of wetland covered by water, and5) number of breeding duck pairs. Basin scale indicators includingsoil phosphorus concentrations and invertebrate taxa richnessshowed some promise; however, plant species richness was the onlystatistically significant basin scale indicator distinguishinggrassland dominated from cropland dominated landscapes. Althoughour study found a number of promising candidate indicators, oneof our conclusions is that basin scale indicators present anumber of implementation problems, including: skill levelrequirements, site access denials, and recession of site accessby landowners. Alternatively, we suggest that the use oflandscape indicators based on remote sensing can be an effectivemeans of assessing wetland integrity.

Environmental Monitoring and Assessment↗
USGS2007

Water Quality in the Tanana River Basin, Alaska, Water Years 2004-06

OVERVIEW This report contains water-quality data collected from 84 sites in Tanana River basin during water years 2004 through 2006 (October 2003 through September 2006) as part of a cooperative study between the U.S. Geological Survey (USGS) and Alaska Department of Environmental Conservation (ADEC) Alaska Monitoring and Assessment Program (AKMAP), supported in part through the U.S. Environmental Protection Agency (USEPA) Office of Water, Cooperative Assistance Agreement X7-97078801. A broad range of chemical analyses are presented for 93 sets of samples collected at 59 tributaries to the Tanana River and at 25 locations along the mainstem. These data are to provide a means to assess baseline characteristics and establish indicators that are ecologically important, affordable, and relevant to society.

Open-File Report↗
USGS2025

Deformity, erosion, lesion, tumor, and parasite (DELT) anomalies in fish communities of the Chesapeake Bay watershed, USA: A regional assessment and potential landscape drivers

Fish diseases in freshwater ecosystems pose significant ecological and socioeconomic challenges, yet monitoring them in wild populations is complex due to interactions between pathogens, hosts, and environmental conditions. We examine the prevalence and watershed-scale landscape drivers of external deformity, erosion, lesion, tumor, and parasite (DELT) anomalies in 57 riverine fish species using a large dataset (577,266 individuals collected 2008–2019) from the Chesapeake Bay watershed that originated from state and federal agencies. Overall, DELT prevalence was low (1.4%), but was higher in larger, longer-lived species, including Channel Catfish ( Ictalurus punctatus ) (18.9%), Rock Bass ( Ambloplites rupestris ) (7.6%), Smallmouth Bass ( Micropterus dolomieu ) (7.3%), Brown Bullhead ( Ameiurus nebulosus ) (5.6%), and Yellow Bullhead ( Ameiurus natalis ) (5.1%), signifying their potential as regional environmental health indicators. Spatial analysis indicated warmer temperatures increased the estimated probability of DELT occurrence, whereas higher precipitation often mitigated the probability of DELT occurrence. Conservation strategies (e.g., best management practices) had mixed effectiveness in reducing DELT occurrence probability across agricultural and urban landscapes. Across the landscape, various drivers, including harvested forest, impervious land, and pesticide use, influenced DELT occurrence probability differently across species. However, uncertainty remains partly due to low prevalence and variability in sampling methods across agencies. Despite low overall prevalence, DELT occurrence is a rapid fish health indicator. Future research could emphasize species-specific responses and longitudinal studies that incorporate life stages and health indicators. Understanding these intricate, multi-scale interactions is vital for effective monitoring, conservation, and adaptive management of freshwater ecosystems.

Chesapeake Bay watershed↗
USGS2014

Monitoring fish distributions along electrofishing segments

Electrofishing is widely used to monitor fish species composition and relative abundance in streams and lakes. According to standard protocols, multiple segments are selected in a body of water to monitor population relative abundance as the ratio of total catch to total sampling effort. The standard protocol provides an assessment of fish distribution at a macrohabitat scale among segments, but not within segments. An ancillary protocol was developed for assessing fish distribution at a finer scale within electrofishing segments. The ancillary protocol was used to estimate spacing, dispersion, and association of two species along shore segments in two local reservoirs. The added information provided by the ancillary protocol may be useful for assessing fish distribution relative to fish of the same species, to fish of different species, and to environmental or habitat characteristics.

Mississippi↗
USGS2018

Spatial factors of white-tailed deer herbivory assessment in the central Appalachian Mountains

Because moderate to over-abundant white-tailed deer ( Odocoileus virginianus ) herbivory impacts biodiversity and can alter community function, ecological benchmarks of herbivory impact are needed to assess deer impacts. We evaluated spatial patterns of deer herbivory and their relation to herbivory assessment by evaluating woody vegetation along 20 transects at each of 30 sites spread across a wide range of deer herd densities and vegetative condition throughout the biodiverse Appalachian Mountains of Virginia, USA. Surprisingly, herbivory patterns and the availability of woody forage generally were unchanged among physiographic regions and land use diversity classes. However, some relationships between browsing pattern and vegetation varied with scale. The total quantity of vegetation browsed on a given site and at the transect scale were related positively to the availability of forage, as the proportion of stems browsed decreased as stem density increased. However, this was only true when all stems were considered equally. When stem densities by species were weighted for deer preference, the proportion of stems browsed had no relationship or increased with stem density. Compared to the value from all transects sampled, on average, the mean of ≥ 3 transects within a site was within 0.1 of the browsing ratio and stem densities were within 0.5 stems m −2 . Our results suggest that one transect per square kilometer with a minimum of three transects may be sufficient for most browsing intensity survey requirements to assess herbivory impacts in the Appalachian region of Virginia. Still, inclusion of spatial factors to help partition variation of deer herbivory potentially may allow for improved precision and accuracy in the design of field herbivory impact assessment methods and improve their application across various landscape contexts.

Virginia↗
USGS1998

Comparison of streambed sediment and aquatic biota as media for characterizing trace elements and organochlorine compounds in the Willamette Basin, Oregon

During 1992-93, 27 organochlorine compounds (pesticides plus total PCB) and 17 trace elements were analyzed in bed sediment and aquatic biota from 20 stream sites in the Willamette Basin as part of the U.S. Geological Survey's National Water-Quality Assessment Program. Data from each medium were compared to evaluate their relative effectiveness for assessing occurrence (broadly defined as documentation of important concentrations) of these constituents. Except for Cd, Hg, Se, and Ag, trace element concentrations generally were higher in bed sediment than in biota. Conversely, although frequencies of detection for organochlorine compounds in biota were only slightly greater than in bed sediment, actual concentrations in biota (normalized to lipid) were as much as 19 times those in sediment (normalized to organic carbon). Sculpin (Cottus spp.) and Asiatic clams (Corbicula fluminea), found at 14 and 7 sites, respectively, were the most widespread taxa collected during the study. Concentrations of trace elements, particularly As and Cu, were typically greater in Asiatic clams than in sculpin. In contrast, almost half of the organochlorine compounds analyzed were found in sculpin, but only DDT and its degradation products were detected in Asiatic clams; this may be related to the lipid content of sculpin, which was about three times higher than for clams. Thus, the medium of choice for assessing occurrence depends largely on the constituent(s) of interest.

Environmental Monitoring and Assessment↗
USGS2011

Development and use of a floristic quality index for coastal Louisiana marshes

The Floristic Quality Index (FQI) has been used as a tool for assessing the integrity of plant communities and for assessing restoration projects in many regions of the USA. Here, we develop a modified FQI (FQImod) for coastal Louisiana wetlands and verify it using 12 years of monitoring data from a coastal restoration project. Plant species that occur in coastal Louisiana were assigned a coefficient of conservatism (CC) score by a local group with expertise in Louisiana coastal vegetation. Species percent cover and both native and non-native species were included in the FQImod which was scaled from 0?100. The FQImod scores from the long-term monitoring project demonstrated the utility of this index for assessing wetland condition over time, including its sensitivity to a hurricane. Ultimately, the FQI developed for coastal Louisiana will be used in conjunction with other wetland indices (e.g., hydrology and soils) to assess wetland condition coastwide and these indices will aid managers in coastal restoration and management decisions.

Louisiana↗
USGS2019

Relations of dissolved-oxygen variability, selected field constituents, and metabolism estimates to land use and nutrients in high-gradient Boston Mountain streams, Arkansas

Continuous monitoring data can be extremely useful for assessing water quality conditions particularly for variables that exhibit dynamic diel swings such as dissolved oxygen. As a means of evaluating dissolved oxygen criteria used by the Arkansas Department of Environmental Quality (ADEQ) for assessing this stream class, we compared continuous dissolved oxygen (DO) data collected at five small- to moderate-sized (watersheds 10-100 mi 2 ), high-gradient streams in the Boston Mountains distributed across a land-use and nutrient condition gradient. The current DO criteria employed by ADEQ for Boston Mountains streams >10 mi2 consists of both an exceedance rate and a magnitude, in which, streams may be considered 'impaired' if greater than 10% of DO measurements during a period of record are < 6 mg/L. The 10% exceedance rate, however, is a commonly used “default” value that requires independent testing for different ecoregion stream classifications. Our findings for the five Boston Mountain streams fit a general pattern established for other aquatic systems (e.g. larger streams, low-gradient streams, and lakes) where increasing land-use intensity generally results in increased nutrient concentrations, which can lead to stream eutrophication and increased DO variability. DO concentrations were < 6 mg/L for fewer than 4% of measurements at the two sites identified “a priori” as least disturbed by nutrient and land-use indices, while concentrations at the three sites identified as moderately and most disturbed were < 6 mg/L for 20 to 33% of measurements. These findings demonstrate that the 10% exceedance rate currently employed by ADEQ was effective at identifying various degrees of DO impairment in Boston Mountain streams. Our analysis also demonstrated that continuous pH and specific conductance data and estimates of stream metabolism were helpful for associating DO variability to anthropogenic or natural origins. Considerations that were useful for examining these relationships and evaluating ADEQ’s DO criteria should be applicable to DO studies in other locations where stream and geologic characteristics are like those of the Boston Mountains.

Arkansas, Oklahoma↗
USGS2000

Evaluation of terrestrial and streamside salamander monitoring techniques at Shenandoah National Park

In response to concerns about amphibian declines, a study evaluating and validating amphibian monitoring techniques was initiated in Shenandoah and Big Bend National Parks in the spring of 1998. We evaluate precision, bias, and efficiency of several sampling methods for terrestrial and streamside salamanders in Shenandoah National Park and assess salamander abundance in relation to environmental variables, notably soil and water pH. Terrestrial salamanders, primarily redback salamanders ( Plethodon cinereus ), were sampled by searching under cover objects during the day in square plots (10 to 35 m 2 ). We compared population indices (mean daily and total counts) with adjusted population estimates from capture-recapture. Analyses suggested that the proportion of salamanders detected ( p ) during sampling varied among plots, necessitating the use of adjusted population estimates. However, adjusted population estimates were less precise than population indices, and may not be efficient in relating salamander populations to environmental variables. In future sampling, strategic use of capture-recapture to verify consistency of p 's among sites may be a reasonable compromise between the possibility of bias in estimation of population size and deficiencies due to inefficiency associated with the estimation of p . The streamside two-lined salamander ( Eurycea bislineata ) was surveyed using four methods: leaf litter refugia bags, 1 m 2 quadrats, 50 × 1 m visual encounter transects, and electric shocking. Comparison of survey methods at nine streams revealed congruent patterns of abundance among sites, suggesting that relative bias among the methods is similar, and that choice of survey method should be based on precision and logistical efficiency. Redback and two-lined salamander abundance were not significantly related to soil or water pH, respectively.

Texas, Virginia↗
USGS2006

Modeling wetland plant community response to assess water-level regulation scenarios in the Lake Ontario-St. Lawrence River basin

The International Joint Commission has recently completed a five-year study (2000-2005) to review the operation of structures controlling the flows and levels of the Lake Ontario - St. Lawrence River system. In addition to addressing the multitude of stakeholder interests, the regulation plan review also considers environmental sustainability and integrity of wetlands and various ecosystem components. The present paper outlines the general approach, scientific methodology and applied management considerations of studies quantifying the relationships between hydrology and wetland plant assemblages (% occurrence, surface area) in Lake Ontario and the Upper and Lower St. Lawrence River. Although similar study designs were used across the study region, different methodologies were required that were specifically adapted to suit the important regional differences between the lake and river systems, range in water-level variations, and confounding factors (geomorphic types, exposure, sediment characteristics, downstream gradient of water quality, origin of water masses in the Lower River). Performance indicators (metrics), such as total area of wetland in meadow marsh vegetation type, that link wetland response to water levels will be used to assess the effects of different regulation plans under current and future (climate change) water-supply scenarios.

Environmental Monitoring and Assessment↗
USGS1977

Clinical methods for the assessment of the effects of environmental stress on fish health

Clinical methods are presented for biological monitoring of hatchery and native fish populations to assess the effects of environmental stress on fish health. The choice of methods is based on the experience of the authors and the judgment of colleagues at fishery laboratories of the U.S. Fish and Wildlife Service. Detailed analysis methods, together with guidelines for sample collection and for the interpretation of results, are given for tests on blood (cell counts, chloride, cholesterol, clotting time, cortisol, glucose, hematocrit, hemoglobin, lactic acid, methemoglobin, osmolality, and total protein); water (ammonia and nitrite content); and liver and muscle (glycogen content).

Technical Paper↗
USGS2025

Tree swallow (Tachycineta bicolor) demographics and metal(loid) concentrations in egg contents from the Kootenai River basin, Montana nest box colonies

Selenium (Se) levels in water have been increasing in Lake Koocanusa and the Kootenai River below Libby Dam in Montana due to coal mining in the drainage basin of the Elk River, British Columbia. Aquatic monitoring of Se is ongoing to assess potential effects; however, exposure to terrestrial, aquatic-dependent wildlife has not been investigated. Tree swallows are a targeted receptor for evaluation of potential Se-related effects as this species is a mid-level consumer with aquatic-terrestrial food web linkages, is sensitive to Se, and reliably uses nest boxes. The goals of this project were to identify tree swallow demographics and metal(loid) concentrations to assess potential species and ecosystem-level effects within the Kootenai River basin study area. During 2022 and 2023, a total of 98 nest boxes were monitored across ~ 120 km of shoreline; 60 eggs were collected. Egg metal(loid) concentrations, including Se, were below levels identified to cause reproductive effects in avian species. However, nest box occupancy increased with distance from the US/Canada border ( P < 0.001; R 2 = 0.83), and Se concentrations were significantly higher ( P = 0.014) in 2023 than 2022 (3.2 (3.0–3.4) and 2.8 (2.6–3.1), respectively; geometric mean, 95% CI; mg/kg, dw). With ongoing mining operations in the drainage basin of the Elk River, these results suggest that long-term monitoring of tree swallows will support assessment of spatiotemporal metal(loid) trends. Additional data, including tree swallow foraging patterns, will allow evaluation of differences in nest box occupancy and metal(loid) concentrations in the Kootenai River basin.

Montana↗
USGS2018

Indicators of exposure to estrogenic compounds at Great Lakes Areas of Concern: Species and site comparisons

Adverse effects resulting from potential exposure of wild fishes to estrogenic endocrine disruptors was assessed at seven United States Great Lakes Areas of Concern using biomarkers ranging from organismal (gonadosomatic indices) to tissue/plasma (histology, plasma vitellogenin) and molecular (hepatic gene transcripts) levels. Biomonitoring was conducted on pelagic, top predator species, largemouth Micropterus salmoides and smallmouth M. dolomieu bass and benthic, omnivorous white sucker Catostomus commersonii. Seasonal (spring and fall) comparisons were conducted at select sites. Intersex (testicular oocytes), plasma vitellogenin and hepatic vitellogenin transcripts were commonly observed in bass species. Testicular oocyte severity was positively, although weakly, correlated with plasma vitellogenin, hepatic transcripts of vitellogenin, estrogen receptor α and estrogen receptor β2, while negatively correlated with androgen receptor β and phosphoenolpyruvate carboxykinase. No testicular oocytes were observed in white sucker, however, plasma vitellogenin and hepatic vitellogenin transcripts were commonly detected in the males. The results demonstrate the importance of utilizing multiple endpoints to assess exposure to estrogenic compounds as well as the importance of choosing sensitive species.

Great Lakes↗
USGS2021

Modeling estrogenic activity in streams throughout the Potomac and Chesapeake Bay watersheds

Endocrine-disrupting compounds (EDCs), specifically estrogenic endocrine-disrupting compounds, vary in concentration and composition in surface waters under the influence of different landscape sources and landcover gradients. Estrogenic activity in surface waters may lead to adverse effects in aquatic species at both individual and population levels, often observed through the presence of intersex and vitellogenin induction in male fish. In the Chesapeake Bay Watershed, located on the mid-Atlantic coast of the USA, intersex has been observed in several sub-watersheds where previous studies have identified specific landscape sources of EDCs in tandem with observed fish health effects. Previous work in the Potomac River Watershed (PRW), the largest basin within the Chesapeake Bay Watershed, was leveraged to build random forest regression models to predict estrogenic activity at unsampled reaches in both the Potomac River and larger Chesapeake Bay Watersheds (CBW). Model outputs including important variables, partial dependence plots, and predicted values of estrogenic activity at unsampled reaches provide insight into drivers of estrogenic activity at different seasons and scales. Using the US Environmental Protection Agency effects-based threshold of 1.0 ng/L 17 β-estradiol equivalents, catchments predicted to exceed this value were categorized as at risk for adverse effects from exposure to estrogenic compounds and evaluated relative to healthy watersheds and recreation access locations throughout the PRW. Results show immediate catchment scale models are more reliable than upstream models, and the best predictive variables differ by season and scale. A small percentage of healthy watersheds (< 13%) and public access sites were classified as at risk using the “Total” (annual) model in the CBW. This study is the first Potomac River Watershed assessment of estrogenic activity, providing a new foundation for future risk assessment and management design efforts, with additional context provided for the entire Chesapeake Bay Watershed.

Delaware, Maryland, New York, Pennsylvania, Virgin↗
USGS2009

Water quality of least-impaired lakes in eastern and southern Arkansas

A three-phased study identified one least-impaired (reference) lake for each of four Arkansas lake classifications: three classifications in the Mississippi Alluvial Plain (MAP) ecoregion and a fourth classification in the South Central Plains (SCP) ecoregion. Water quality at three of the least-impaired lakes generally was comparable and also was comparable to water quality from Kansas and Missouri reference lakes and Texas least-impaired lakes. Water quality of one least-impaired lake in the MAP ecoregion was not as good as water quality in other least-impaired lakes in Arkansas or in the three other states: a probable consequence of all lakes in that classification having a designated use as a source of irrigation water. Chemical and physical conditions for all four lake classifications were at times naturally harsh as limnological characteristics changed temporally. As a consequence of allochthonous organic material, oxbow lakes isolated within watersheds comprised of swamps were susceptible to low dissolved oxygen concentrations to the extent that conditions would be limiting to some aquatic biota. Also, pH in lakes in the SCP ecoregion was <6.0, a level exceeding current Arkansas water-quality standards but typical of black water systems. Water quality of the deepest lakes exceeded that of shallow lakes. N/P ratios and trophic state indices may be less effective for assessing water quality for shallow lakes (<2 m) than for deep lakes because there is an increased exposure of sediment (and associated phosphorus) to disturbance and light in the former. ?? 2009 Springer Science+Business Media B.V.

Environmental Monitoring and Assessment↗